In mobile networks, such as a 3GPP (Third Generation Partnership Project) mobile network, various types of terminal devices may be used. For example, Machine Type Communication (MTC) terminal devices may be used in addition to conventional types of terminal devices, in the following also termed as user equipment (UE), such as mobile phones, smartphones, data modems, mobile computers, or the like. MTC terminal devices typically transmit and receive only small amounts of data, which may occur more or less infrequently, e.g., once per week to once per minute. MTC terminal devices may also be polled for data, resulting in an irregular pattern of data transmission. MTC terminal devices are typically assumed to be autonomous sensor devices, alarm devices, actuator devices, remote control devices, or the like, which communicate with application servers, rather than being used for communication by a human user. Hence, this type of communication may also be referred to as machine-to-machine (M2M) communication and the devices may be denoted machine devices (MDs). An application server may in turn configure the MTC terminal device and receive data from them. The application server may be within or outside the mobile network.
Considering the above, MTC terminal devices are typically characterized by a modest bit rate and sparse communication. MTC terminal devices may therefore be implemented with low-performance data transmission capabilities. Further, MTC devices typically need to be very energy efficient, since external power supplies may not be available and/or it may be practically or economically not feasible to frequently replace or recharge their batteries.
A known way of energy saving in a UE, which may also be applied to MTC devices, is to use Discontinuous Reception (DRX). By means of DRX, a UE can enter an energy efficient sleep mode when no data transmission is needed. In the sleep mode, receiver circuitry of the UE is turned of. However, DRX does not address energy consumption during actual data transmission, when the receiver circuitry needs to be active. Also, DRX may for example lack efficiency if large amounts of data need to be transmitted from time to time.
Accordingly, there is a need for techniques which allow for energy saving during actual data transmission to or from a terminal device.